Aeration apparatus and methods

ABSTRACT

A soil aeration apparatus can include an aeration rotor comprising at least one set of aeration tines configured for movement in a planetary motion about an axis. The apparatus can further include the aeration rotor being configured to remove soil plugs from a ground surface and break the soil plugs into soil particles when the aeration rotor is rotated.

TECHNICAL FIELD

This document relates to treating a ground surface, such as a system foraerating a ground surface.

BACKGROUND

Soil aeration is a conventional technique used by groundskeepers toreduce compaction in the ground soil, stimulate plant growth, andpromote proper drainage. Soil may become compacted from overuse orenvironmental effects, which ultimately affects the soil permeabilityand development of rooted plants within the soil. In particular,compacted soil restricts the amount of oxygen that can enter the soiland the amount of carbon dioxide that can escape. Not all soils areaffected equally by overuse and environmental factors. The amount ofcompaction depends on soil composition, the amount of vegetation, andthe moisture content of the soil. Periodic soil aeration relieves thecompaction in the soil before the negative effects overburden the soilto the point that it can no longer support desirable vegetation.

Some conventional soil aeration systems penetrate the ground usingcoring tubes that penetrate the ground and remove “plugs” of soil. Whenthe plugs of soil are removed from the ground, the treated groundsurface is littered with the soil plugs. In other aeration systems, asoil aeration apparatus may include a set of aeration blades that cutthe soil so as to form the aeration pockets. In these cases, there areno plugs of soil that are removed from the ground and littered acrossthe ground surface. Soil aeration systems can be relatively complex,bulky, heavy, and consequently expensive and complex to manufacture andoperate.

SUMMARY

Some embodiments of a soil aeration apparatus can include one or more ofthe features and functions disclosed herein. Some embodiments of a soilaeration apparatus can be sized and configured to be relatively smalland light weight. Some embodiments of a soil aeration apparatus can beconfigured to for use as a walk-behind or push soil aeration apparatus.Some embodiments of a soil aeration apparatus can be configured to pullsoil plugs from a ground surface and break the soil plugs into soilparticles to be returned to the ground surface.

In one aspect, a soil aeration apparatus can include an aeration rotorwith a carrier and a plurality of aeration tines supported by thecarrier. The rotor is configured to drive the aeration tines topenetrate soil and remove soil plugs from the soil when the aerationrotor is rotated. The apparatus may further include a shield defining arotor cavity and at least partially surrounding the aeration rotorpositioned in the rotor cavity. The shield defines at least one tineport sized and positioned to allow for ingress and egress of theaeration tines during rotation of the rotor. The shield defines aplurality of sifting ports sized small enough to retain soil plugswithin the rotor cavity (e.g., until the plugs are broken) and largeenough to allow soil particles from broken soil plugs to pass throughthe sifting ports out of the rotor cavity.

In one aspect, a soil aeration apparatus includes a frame connected toat least two wheels for travelling over a ground surface, the framehaving a handle positioned and configured to facilitate a user to pushthe soil aeration apparatus. The apparatus further includes an aerationrotor operably supported by the frame. The aeration rotor includes firstand second carriers rotatable with respect to the frame about a firstaxis. The aeration rotor includes a first tine-holder shaft extendingbetween the first and second carriers, the first tine-holder shaftsupporting a first set of aeration tines. The first tine-holder shaft isrotatable with respect to the first carrier about a second axis. Theaeration rotor includes a second tine-holder shaft extending between thefirst and second carriers, the second tine-holder shaft supporting asecond set of aeration tines. The second tine-holder shaft is rotatablewith respect to the first carrier about a third axis. The apparatusfurther includes a motor supported by the frame and operably connectedto the aeration rotor to drive rotation of the aeration rotor such thatthe aeration tines can penetrate and exit the ground when the aerationrotor is rotated.

In one aspect, a soil aeration apparatus includes an aeration rotorcomprising at least one set of aeration tines configured for movement ina planetary motion about an axis. The apparatus further includes a motoroperably connected to the aeration rotor to drive rotation of theaeration rotor such that the aeration tines can penetrate and exit aground surface when the aeration rotor is rotated. The apparatus furtherincludes a frame supporting the aeration rotor and the motor and havinga handle configured to be held by a user walking behind the soilaeration apparatus.

In one aspect, a soil aeration apparatus includes an aeration rotorcomprising at least one set of aeration tines configured for movement ina planetary motion about an axis. The apparatus further includes theaeration rotor being configured to remove soil plugs from a groundsurface and break the soil plugs into soil particles when the aerationrotor is rotated.

Implementations of the above-described apparatuses can include any, all,or none of the following features. The aeration rotor includes first andsecond carriers rotatable about a first axis. The aeration rotorincludes a first tine-holder shaft extending between the first andsecond carriers, the first tine-holder shaft supporting a first set ofaeration tines, wherein the first tine-holder shaft is rotatable withrespect to the first carrier about a second axis. The aeration rotorincludes a second tine-holder shaft extending between the first andsecond carriers, the second tine-holder shaft supporting a second set ofaeration tines, wherein the second tine-holder shaft is rotatable withrespect to the first carrier about a third axis. Rotation of the firstand second tine-holder shafts turns the first and second sets ofaeration tines to sweep through the first axis. The aeration rotorrotates in a first direction and the first and second tine-holder shaftsrotate in a second direction during rotation of the aeration rotor inthe first direction. The aeration rotor has a radius extending from thefirst axis to each of the second and third axes of about 3.5 inches. Theaeration rotor has a radius extending from the first axis to each of thesecond and third axes of between about 3 inches to about 4 inches. Theaeration rotor has a radius extending from the first axis to each of thesecond and third axes of between about 2 inches to about 6 inches. Atleast some of the plurality of aeration tines have a length exceedingthe radius. The shield defines a second tine port sized and positionedto allow for ingress and egress of the aeration tines during rotation ofthe rotor, wherein the aeration tines extend out of the shield only atthe first and second tine ports during rotation of the rotor. The shieldincludes a front shield positioned forward of the aeration rotor and arear shield positioned behind the aeration rotor, wherein each of thefront and rear shields define a plurality of the sifting ports sizedsmall enough to contain soil plugs within the rotor cavity and largeenough to allow soil particles from broken soil plugs to pass throughthe sifting ports out of the rotor cavity. The aeration rotor includes apulverizing bar configured for pulverizing soil plugs into soilparticles in the rotor cavity. The pulverizing bar is positioned betweenabout 0.05 inch and about 0.2 inch from an inner surface of the shield.Each of the aeration tines includes a knife and a tube connected to theknife, wherein the aeration rotor and aeration tines are configured topull soil plugs from a ground surface and fling the soil plugs into therotor cavity to be pulverized into soil particles by the aeration rotorwithin the rotor cavity. The soil aeration apparatus includes a motoroperably connected to the aeration rotor to drive rotation of theaeration rotor and a relief spring system connected between the motorand the aeration rotor and configured to allow for some rotation by themotor when rotation of the aeration tines is temporarily slowed orstopped. Spring capacity of the relief spring system is equal to orgreater than weight of the soil aeration apparatus. The spring capacityof the relief spring system is between about 150 pounds and about 600pounds and the soil aeration apparatus weighs between about 100 poundsand about 500 pounds. The soil aeration apparatus includes a frameconnected to at least two wheels for travelling over a ground surface,the frame supporting the rotor and having a handle positioned andconfigured to facilitate a user to push the soil aeration apparatus.

In one aspect, a method of operating a soil aeration apparatus includesmoving a set of aeration tines in a planetary motion such that theaeration tines revolve about a first axis and rotate about a second axisdifferent than the first axis. The method further includes removing soilplugs from a ground surface via the aeration tines. The method furtherincludes breaking the soil plugs into soil particles via components ofthe soil aeration apparatus. The method further includes returning thesoil particles to the ground surface.

Implementations can include any, all, or none of the following features.The method including flinging the soil plugs from the aeration tinesinto a rotor cavity, wherein the soil plugs are broken into soilparticles in the rotor cavity. The method including passing the soilparticles through sifting ports sized small enough to restrict passageof the soil plugs and large enough to allow passage of the soilparticles from broken soil plugs. The method including walking behindthe soil aeration apparatus and holding a handle of the soil aerationapparatus while operating the soil aeration apparatus to remove andbreak soil plugs.

Some or all of the embodiments described herein may provide one or moreof the following advantages. First, some embodiments of the aerationapparatus provide a planetary aeration path for each tine so as toremove a small plug of soil, yet the aeration apparatus can beconfigured to reduce the likelihood of the soil plugs littering theground after the plugs are removed. Rather, the rotor cavity of theaeration apparatus can break apart the some or all of the soil plugsbefore the soil is returned to the ground surface (for example, via thesifting ports of the shield).

Second, some embodiments of the aeration apparatus may be configured toprovide a light-weight, convenient aerator in which a user can simplywalk behind the aeration apparatus during operation. For example, theaeration apparatus may be relatively light (as compared to sometraditional aerators having planetary aeration apparatus), such asweighing 180 lbs. or less in total (and, optionally, the rotor deviceweighing less than 50 lbs.). Additionally, the aeration apparatus may beprovided in a set of sizes (e.g., a width of about 20 inches to about 50inches, and preferably a width selected from the group consisting ofabout 21 inches, about 29, inches, about 37 inches, and about 45inches), so that a user walking behind the apparatus can readilytransport and turn the apparatus during operation. Reducing size andweight of the aeration apparatus can also reduce the amount ofhorsepower and fuel consumption required for operation.

The details of one or more embodiments of the invention are set forth inthe accompa-nying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective top view of a soil aeration apparatus inaccordance with an embodiment of the invention.

FIG. 2 is a perspective bottom view of the soil aeration apparatus ofFIG. 1.

FIG. 3 is a perspective view of the soil aeration apparatus of FIG. 1with portions of a housing removed.

FIG. 4 is a perspective view of an aeration rotor of the soil aerationapparatus of FIG. 1.

FIGS. 5A-5C are schematic side sectional views of the aeration rotor atdifferent angles of rotation.

FIG. 6 is a perspective view of an aeration tine for use in the soilaeration apparatus of FIG. 1.

FIG. 7 is a top view of the aeration tine of FIG. 6.

FIG. 8 is a side view of the aeration tine of FIG. 6.

FIG. 9 is an end view of a connecting end of the aeration tine of FIG.6.

FIG. 10 is an end view of a distal end of the aeration tine of FIG. 6.

FIG. 11 is a sectional view of the aeration tine taken along line 11-11of FIG. 8.

FIG. 12 is a sectional view of the aeration tine taken along line 12-12of FIG. 7.

FIG. 13 is a sectional view of the aeration tine taken along line 13-13of FIG. 8.

FIG. 14 is a sectional view of the aeration tine taken along line 14-14of FIG. 8.

FIG. 15 is a sectional view of the aeration tine taken along line 15-15of FIG. 12.

FIGS. 16-17 are top views of a ground surface having soil aerated inaccordance with certain embodiments of the invention.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1, some embodiments of a soil aeration apparatus 10include a frame 12 which includes a handle 14 and a housing 16. Theframe 12 is connected to a pair of wheels 18 and 20, which areconfigured for traveling over a ground surface 22 to facilitate movementof the soil aeration apparatus 10. The housing 16 surrounds and at leastpartially encloses components of the soil aeration apparatus 10. In theillustrated embodiment, the housing 16 is part of the frame 12,providing structural support for the soil aeration apparatus 10. A motor24 is mounted to and supported by the housing 16. The handle 14 ismounted to and supported by the housing 16. In other embodiments, thehousing 16 need not be part of the frame 12, but rather can be anon-structural enclosure supported by the frame 12.

In the illustrated embodiment, the wheel 18 is a front wheel and thewheel 20 is a rear wheel. The handle 14 can be mounted in a position andconfigured to facilitate a user to walk behind and push the soilaeration apparatus 10. For example, in the illustrated embodiment thehandle 14 is a substantially U-shaped handle with ends mounted to leftand right sides of the housing 16 so as to extend rearward behind thesoil aeration apparatus 10.

In some embodiments, the motor 24 can be operably connected to one ormore of the wheels 18 and 20 so as to drive movement of the soilaeration apparatus 10 with or without force provided by the user. Thesoil aeration apparatus 10 can be operated as a push or walk-behindsystem without requiring a vehicle to tow or otherwise propel the soilaeration apparatus 10. In other embodiments, the soil aeration apparatus10 can be modified for use with a towing vehicle.

The soil aeration apparatus 10 includes a shield 26 defining a rotorcavity 28 and at least partially surrounding an aeration rotor 30 in therotor cavity 28. The shield 26 defines sifting ports 32 extendingthrough the shield 26 to create a passage from the rotor cavity 28 to anexterior of the shield 26. Visibility of the rotor cavity 28 and theaeration rotor 30 are obscured as seen in FIG. 1 but can be partiallyseen through the sifting ports 32.

The sifting ports 32 can be sized small enough to contain soil plugs(not shown in FIG. 1) within the rotor cavity 28 and large enough toallow soil particles (not shown in FIG. 1) from broken soil plugs topass through the sifting ports 32 and out of the rotor cavity 28. Insome embodiments the shield 26 can be formed of sheet metal. In someembodiments, the shield 26 can be formed of a mesh or screen.

The shield 26 can be formed of aluminum, carbon steel, or an alloythereof. In the illustrated embodiment, the shield 26 is formed of acurved sheet of aluminum metal having three rows of laterally-elongatedsifting ports 32. In other embodiments, the shield 26 can be formed of awire mesh of metal (e.g. steel) that defines the sifting ports 32between wires. In some embodiments, all or most of the frame 12(including the housing 16 and shield 26) can be formed of aluminum or analuminum alloy so as to reduce overall weight of the soil aerationapparatus 10. In such embodiments, the aeration rotor 30 can be made ofa material that is heavier and stronger than aluminum, such as carbonsteel, so that the soil aeration apparatus 10 can be both relativelylight-weight and durable as suitable for its application.

Referring to FIG. 2, the shield 26 can be a shield system that includesa front shield 34 and a rear shield 36 that combine to define the rotorcavity 28. The shield 26 defines a bottom tine port 38 between edges ofthe front shield 34 and the rear shield 36. The bottom tine port 38 isan elongated opening between the front shield 34 and the rear shield 36that extends substantially a full length of the aeration rotor 30. Thebottom tine port 38 is sized and positioned to allow for ingress andegress of a plurality of aeration tines 40 that are attached to and partof the aeration rotor 30. The bottom tine port 38 is positioned at abottom of the soil aeration apparatus 10 to allow the aeration tines 40to extend out of the rotor cavity 28 to penetrate soil and remove soilplugs from the soil when the aeration rotor 30 is rotated.

Referring to FIG. 3, in this embodiment, the motor 24 is connected to agear system 42 that can drive one or more of the wheel 18, the wheel 20,and the aeration rotor 30. In the illustrated embodiment, the gearsystem 42 includes a series of gears connecting the motor 24 to each ofthe wheel 18, the wheel 20, and the aeration rotor 30 to transmit forceand motion from the motor 24 to the wheel 18, the wheel 20, and theaeration rotor 30. In some embodiments, the gear system 42 can includebelts and/or chains (not shown) in addition to or instead of gears.

In some embodiments, the soil aeration apparatus 10 can have a reliefspring system 44 connected to the gear system 42. The relief springsystem 44 can include one or more springs 46 and 48 connected to alinkage 50 allowing for relief when the aeration tines 40 aretemporarily slowed or stopped, such as one or more of the aeration tines40 of the aeration rotor 30 hitting a rock. The relief spring system 44can be connected between the motor 24 and the aeration tines 40 to allowfor some rotation by the motor 24 even when rotation of the aerationtines 40 is temporarily slowed or stopped. Rotation of the aerationtines 40 can be slowed in response to hitting a rock, the relief springsystem 44 can be compressed, and the aeration tines 40 can then reboundand continue operation. This can reduce jerking and damage caused tocomponents of the soil aeration apparatus 10, such as gears or chains ofthe gear system 42. Because the relief spring system 44 can reducejerking, forces, and damage caused to components of the soil aerationapparatus 10, such components can be made smaller and lighter weight.Horsepower required for operation can be reduced, allowing for the motor24 to also be smaller, lighter weight, and more fuel efficient. Thus, insome embodiments, use of the relief spring system 44 can reduce overallweight and fuel consumption of the soil aeration apparatus 10.

In some embodiments, spring capacity of the relief spring system 44 canbe equal to or greater than the weight of the soil aeration apparatus10. This can allow the relief spring system 44 to effectively providerelief for all or nearly all possible force conditions. For example, ifone or more of the aeration tines 40 of the aeration rotor 30 hits arock causing a force that is less than the capacity of the relief springsystem 44, then the relief spring system 44 can absorb that force. If,however, one or more of the aeration tines 40 of the aeration rotor 30hits a rock causing a force that is greater than the capacity of therelief spring system 44, that force will also be greater than the weightof the soil aeration apparatus 10 so long as spring capacity of therelief spring system 44 is equal to or greater than the weight of thesoil aeration apparatus 10. The relief spring system 44 can absorb someof the applied force and the soil aeration apparatus 10 can be lifted bythat force to effectively absorb the rest of that force.

In some embodiments, the soil aeration apparatus 10 can weigh about 180pounds or less and the spring capacity of the relief spring system 44can be about 250 pounds or more. In some embodiments, the soil aerationapparatus 10 can weigh between about 150 pounds and about 250 pounds. Insome embodiments, the soil aeration apparatus 10 can weigh between about100 pounds and about 500 pounds. In some embodiments, the springcapacity of the relief spring system 44 can be between about 200 poundsand about 300 pounds. In some embodiments, the spring capacity of therelief spring system 44 can be between about 150 pounds and about 600pounds. In other embodiments, weight of the soil aeration apparatus 10and spring capacity of the relief spring system 44 can have differentvalues suitable for the application.

Referring to FIG. 4, the aeration rotor 30 includes two opposingcarriers 52 and 54 and includes two tine-holder shafts 56 and 58extending between the carriers 52 and 54. The tine-holder shafts 56 and58 are rotatably mounted to the carriers 52 and 54 such that each shaftcan rotate about its own axis. The carriers 52 and 54 can be rotatablewith respect to the frame 12 (shown in FIGS. 1 and 2) about a first axisA1, the tine-holder shaft 56 can be rotatable with respect to thecarriers 52 and 54 about a second axis A2, and the tine-holder shaft 58can be rotatable with respect to the carriers 52 and 54 about a thirdaxis A3.

The tine-holder shafts 56 and 58 are positioned substantially parallelin an axial direction, and the aeration tines 40 extend from eachtine-holder shaft 56 and 58 in a radial direction. The aeration tines 40can penetrate and remove a portion of soil from a ground surface. Twonon-centrally located shafts 60 and 62 also extend between the opposingcarriers 52 and 54. The shafts 60 and 62 can be fixedly mounted to thecarriers 52 and 54 and provide mechanical support for the soil aerationapparatus 10 when in operation.

The gear system 42 is engaged with the tine-holder shafts 56 and 58 tocause rotation of the tine-holder shafts 56 and 58. The gear system 42has a plurality of planetary gears 64 and 66 for each sun gear 68. Eachof the tine-holder shafts 56 and 58 has a planetary gear 64 or 66attached thereto. In some embodiments, the sun gear 68 can be positionedbetween the planetary gears 64 and 66 and engaged with the planetarygears 64 and 66 using a drive chain (not shown). Because two planetarygears 64 and 66 are operated using an individual sun gear 68, thebulkiness of the gear system 42 can be reduced. The aeration rotor 30need not use a centrally located support shaft and the tine-holdershafts 56 and 58 can be positioned closer to one another, thus reducingoverall size of the soil aeration apparatus 10. Rotation of thetine-holder shafts 56 and 58 can turn the aeration tines 40 to sweepthrough a central portion of the aeration rotor 30, overlapping theaeration tines 40 on the tine-holder shaft 56 with the aeration tines 40on the tine-holder shaft 58 such that the aeration tines 40 on both ofthe tine-holder shafts 56 and 58 sweep through the first axis A1.

In some embodiments, the aeration rotor 30 can have a radius extendingfrom the first axis A1 to each of the second and third axes A2 and A3 ofabout 3.5 inches. In some embodiments, the aeration rotor 30 can have aradius extending from the first axis A1 to each of the second and thirdaxes A2 and A3 of between about 3 inches to about 4 inches. In someembodiments, the aeration rotor 30 can have a radius extending from thefirst axis A1 to each of the second and third axes A2 and A3 of betweenabout 2 inches to about 6 inches. Some or all of the aeration tines 40can exceed the radius of the aeration rotor 30.

The planetary gear 64 can be axially aligned with the tine-holder shaft56 and fixedly mounted to a portion of the tine-holder shaft 56extending through the carrier 52. Similarly, the planetary gear 66 canbe axially aligned with the tine-holder shaft 58 and mounted to aportion of the tine-holder shaft 58 extending through the carrier 52. Insome embodiments, the planetary gears 64 and 66 can be aligned with thesun gear 68 such that a single drive chain can be engaged with all threegears 64, 66, and 68. The sun gear 68 can be axially aligned with thefirst axis A1 of the carriers 52 and 54 and remain substantially fixedas the carriers 52 and 54 rotate. When the carriers 52 and 54 rotate,the tine-holder shafts 56 and 58 can be driven to revolve around thefirst axis A1. Likewise, the planetary gears 64 and 66 can also revolvearound the first axis A1. As such, the planetary gears 64 and 66 revolveabout the sun gear 68 as the drive chain causes the planetary gears 64and 66 to rotate. The motion of revolving the tine-holder shafts 56 and58 about the first axis A1 while rotating the tine-holder shafts 56 and58 about the second and third axes A2 and A3 can cause motion of thetines 40 to penetrate and remove soil plugs from the ground surface 22(shown in FIG. 1). Gear ratio of the sun gear 68 to the planetary gears64 and 66 can be 2:1 such that the tine-holder shafts 56 and 58 gothrough two revolutions for every revolution of the aeration rotor 30.

The shafts 60 and 62 can be positioned between the carriers 52 and 54and mounted near a perimeter of each carrier 52 and 54. Because theshafts 60 and 62 are non-centrally located (e.g., offset from the firstaxis A1), the tine-holder shafts 56 and 58 may be positioned closer tothe first axis A1 without interference from the tines 40 hitting acentrally located shaft that may be present in other designs. Rather,the tine-holder shafts 56 and 58 may rotate as the tines 40 pass throughthe first axis A1 without interference. A compact arrangement of shafts56, 58, 60, and 62 can reduce overall size of the soil aerationapparatus 10 in comparison to other apparatuses.

FIGS. 5A-5C are schematic side sectional views of the aeration rotor 30at different angles of rotation. The aeration tine 40A is one of theaeration tines 40 (shown in FIGS. 2-4) attached to the tine-holder shaft58. The aeration tine 40A has a proximal connecting end 70 that isconnected to the tine-holder shaft 58 and a distal end 72 extending awayfrom the tine-holder shaft 58. The aeration tine 40A has a knife 74extending from the connecting end 70 to the distal end 72 and has a tube76 attached to a rear edge of the knife 74. The knife 74 can beconfigured for cutting a hole in the ground surface 22 and the tube canbe configured for pulling a soil plug from the ground surface 22. FIGS.5A-5C are shown with those aeration tines 40 that can be attached to thetine-holder shaft 56 omitted. In some embodiments, aeration tines 40 canbe removed and replaced from the tine-holder shafts 56 and 58 when wornor damaged.

The shield 26 includes the front shield 34 and the rear shield 36 withthe aeration rotor 30 positioned there-between. The shield 26 definesthe bottom tine port 38 substantially below the aeration rotor 30 and atop tine port 78 substantially above the aeration rotor 30. In someembodiments, the bottom tine port 38 and the top tine port 78 can eachbe positioned slightly off-center with respect to the axis A1. Thebottom and top tine ports 38 and 78 are each defined between the frontshield 34 and the rear shield 36. In other embodiments, the shield 26can be formed of a single component (or multiple components) with one ormore tine ports at each of the top and bottom of the shield 26. In someembodiments the bottom and top tine ports 38 and 78 can extendsubstantially an entire length of the aeration rotor 30. In otherembodiments, the bottom and top tine ports 38 and 78 can extend only aportion of the length of the aeration rotor 30.

Referring to FIGS. 5A-5C, during operation, the soil aeration apparatus10 can moved in a forward direction (e.g., from left to right withrespect to the view shown in FIGS. 5A-5C) while the aeration rotor 30provides the planetary motion for the aeration tines. In particular, theaeration rotor 30 can rotate in a counter-clockwise direction (withrespect to the view shown in FIGS. 5A-5C), and the tine-holder shafts 56and 58 as well as the aeration tines 40 can rotate in a clockwisedirection (with respect to the view shown in FIGS. 5A-5C). The aerationtines 40 can exit and re-enter the rotor cavity 28 at each of the bottomand top tine ports 38 and 78 during a full rotation of the aerationrotor 30. With a gear ratio of 2:1, the tine-holder shafts 56 and 58 gothrough two revolutions for every revolution of the aeration rotor 30and thus exit the rotor cavity only twice: once at the bottom tine port38 and once at the top tine port 78. In some embodiments, the aerationrotor 30 can operate to assist in propelling the soil aeration apparatus10 forward as the aeration rotor 30 drives the aeration tines 40 intothe ground surface 22.

As shown in FIG. 5A, the distal end 72 of the aeration tine 40A has justexited through the bottom tine port 38 and is beginning to penetrate theground surface 22. The aeration rotor 30 can continue rotating so as tocause the aeration tine 40A to further penetrate the ground surface 22.

FIG. 5B shows the aeration tine 40A extending into a hole 79, which canbe an aeration pocket formed in the ground surface 22 by the aerationtine 40A. The aeration tine 40A is shown in a substantially verticalorientation. The aeration tine 40A can have a shape and path of movementconfigured for cutting the hole 79 with a vertical or substantiallyvertical forward edge. The aeration rotor can continue rotation so as tocause the aeration tine 40A to exit the ground surface 22.

FIG. 5C shows the aeration tine 40A exiting the hole 79 in the groundsurface 22. As shown in FIG. 5C, the aeration tine 40A has pulled a soilplug 80 from the hole 79. The aeration tine 40A can have a shape andpath of movement configured for cutting a relatively narrow hole 79 fromits forward edge to its rear edge. In some embodiments, the hole 79 canbe sized and shaped differently than as illustrated.

Motion of the aeration tine 40A can cause the aeration tine 40A to throwor fling the soil plug 80 out of the tube 76 and into the rotor cavity28. In some embodiments, the aeration rotor 30 can be configured andoperated such that the soil plug 80 can be thrown into one of the shafts60 and 62, which can act as pulverizing bars to pulverize the soil plug80 into soil particles 82. The soil plug 80 can be pulverized by theshafts 60 and 62, the tine-holder shafts 56 and 58, and the aerationtines 40 as the aeration rotor 30 rotates. The soil plug 80 can bepulverized by components of the aeration rotor 30 until the soil plug 80has broken into soil particles small enough to pass through the siftingports 32 (shown in FIG. 1) out of the rotor cavity 28. This can allowsoil pulled as a soil plug 80 to be returned to the ground surface 22 assoil particles 82. This can reduce or eliminate the number of soil plugs80 left on the ground surface 22, which can be considered unsightly tosome users.

In some embodiments, the shafts 60 and 62 can be positioned near innersurfaces of the shield 26 so as to grind the soil plug 80 against theshield 26. In some embodiments, the shafts 60 and 62 can be positionedabout 0.1 inch from the inner surface of the shield 26. In someembodiments, the shafts 60 and 62 can be positioned between about 0.05inch and about 0.2 inch from the inner surface of the shield 26.

In some embodiments, the shafts 60 and 62 can be shaped and configureddifferently than as illustrated. For example, in some embodiments, theshafts 60 and 62 can have a square or rectangular cross-section. In someembodiments, the shafts 60 and 62 can include one or more brushes (notshown) configured to brush the soil plug 80 against the shield 26.

In some embodiments, the shafts 60 and 62 can include one or more scoops(not shown) or other projections configured to strike and pulverize thesoil plug 80 during operation. Brushes and/or other projections on theshafts 60 and 62 can also function to dethatch the aeration tines 40during operation.

Referring now to FIGS. 6-10, in some embodiments, the knife 74 of theaeration tine 40A may include a concave rear surface 84 extending alonga rear of the knife 74. The concave rear surface 84 can be aligned withthe tube 76 (FIG. 6) so as to flip the soil plug 80 (shown in FIG. 5A)when the soil plug 80 is thrown from the tube 76. FIG. 7 is a top viewof the aeration tine 40A. FIG. 8 is a side view of the aeration tine40A. FIG. 9 is an end view of the connecting end 70 of the aeration tine40A. FIG. 9 shows the aeration tine 40A having a threaded bore 86 at theconnecting end 70 that can be configured for connecting to thetine-holder shafts 56 and 58. FIG. 10 is an end view of the distal end72 of the aeration tine 40A.

FIG. 11 is a sectional view of the aeration tine 40A taken along line11-11 of FIG. 8. FIG. 12 is a sectional view of the aeration tine 40Ataken along line 12-12 of FIG. 7. FIG. 13 is a sectional view of theaeration tine 40A taken along line 13-13 of FIG. 8. FIG. 14 is asectional view of the aeration tine 40A taken along line 14-14 of FIG.8. FIG. 15 is a sectional view of the aeration tine 40A taken along line15-15 of FIG. 12. The aeration tine 40A has a shape suitable for cuttingand pulling soil plugs 80 from the ground surface 22 in some embodimentsof the soil aeration apparatus 10. In some embodiments, the aerationtine 40A can be modified as suitable for the application. In someembodiments, the aeration tine 40A can be replaced with an alternativeaeration tine, such as an aeration tine having a knife similar to theknife 74 but without a tube similar to the tube 76.

FIGS. 16-17 are top views of the ground surface 22 having soil aeratedin accordance with particular embodiments of the soil aeration apparatus10 (e.g., such as the embodiment depicted in FIGS. 1-3). FIG. 16 showssoil aerated using aeration tines 40 (shown in FIGS. 2-15). As the soilaeration apparatus 10 moves over the ground surface 22 in a forwarddirection, the aeration tines 40 can execute penetration, sweeping, andsoil plug removal actions described above to form the holes 79. Each rowof holes 79 can be staggered with respect to the neighboring rows due tothe aeration tines 40 being in a staggered position relative to theaeration tines 40 on the neighboring tine-holder shaft 56 or 58. In FIG.17, the ground surface 22 can be aerated using aeration blades (notshown) similar to the aeration tine 40A but with the tube 76 omitted.Such aeration blades can form holes 88 in the ground surface 22 toaerate the soil as the soil aeration apparatus moves in the forwarddirection. Holes 88 can be narrower than the holes 79 (shown in FIG. 16)due to not including a tube for removing a soil plug.

Staggering the position of the holes 79 and 88 (shown in FIGS. 16 and17) can increase the perforation density (number of holes/slits in agiven area) in the ground surface 22, thus greatly reducing soilcompaction with a single pass of the soil aeration apparatus 10. Ifrotational velocity of the aeration rotor 30 is increased relative toland speed, the holes 79 and 88 can be located closer together. Ifdesired, the holes 79 and 88 can overlap other holes 79 and 88 so as toform a continuous slit. Density of these staggered holes 79 and 88 (i.e.the number of pockets per unit area of turf) can be significantlygreater than that obtained by conventional systems.

Various embodiments of the soil aeration apparatus described above canperform relatively efficient and high quality aeration of ground surfacesoil. Operation of an aeration rotor with one or more shields can allowa soil aeration apparatus to pull soil plugs and pulverize those soilplugs to soil particles to be returned to the ground surface. Includingsifting ports in the shield can allow the shield to retain soil plugs inthe rotor cavity and allow smaller soil particle to pass. Features andcomponents of the aeration rotor can be configured for improvedpulverizing of the soil plug. Various features and components of thesoil aeration apparatus can also facilitate the soil aeration apparatusbeing simpler, smaller, and lighter weight. For example, certainfeatures of the aeration rotor can allow the aeration rotor to besmaller and lighter-weight as compared to some rotor designs.Configuring the aeration rotor to include no central shaft, allows theaeration tines to rotate through a central axis of the aeration rotorand thus allows for a smaller radius of the aeration rotor. Use oflight-weight materials, such as aluminum, for certain components (suchas frame and housing) while using heavier and stronger materials forcomponents experiencing greater load and wear (such as aeration rotor)can reduce overall weight of the soil aeration apparatus whilemaintaining durability. The aeration rotor can be configured with asimpler design that uses less power and that can help propel the soilaeration apparatus during operation. This can allow the soil aerationapparatus to have a smaller motor and a smaller, lighter overallstructure. Configuring the soil aeration apparatus to be a push orwalk-behind apparatus can allow for operation of a smaller soil aerationapparatus operable in smaller spaces and/or without a tow vehicle.Various features described above can help reduce overall cost andcomplexity as compared to some designs, making some embodiments of thesoil aeration apparatus easier and more affordable to manufacture andoperate.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, the specific shape and orientation of various components suchas the gear system, the housing, the wheels, and the aeration rotor canbe modified from those illustrated in the figures so long as the soilaeration apparatus is suitable for a desired application. While the soilaeration apparatus is illustrated as a relatively small, walk-behindapparatus that can pulverize soil cores, other embodiments can includefeatures described above for a towable soil aeration apparatus thatpulverizes soil cores and still other embodiments can include featuresdescribed above for a relatively small, walk-behind apparatus that cutsholes but does not pull cores. Thus, various embodiments of a soilaeration apparatus can include some but not all of the featuresdescribed above. Accordingly, other embodiments are within the scope ofthe following claims.

What is claimed is:
 1. A soil aeration apparatus comprising: an aerationrotor comprising a carrier and a plurality of aeration tines supportedby the carrier, wherein the rotor is configured to drive the aerationtines to penetrate soil and remove soil plugs from the soil when theaeration rotor is rotated; and a shield defining a rotor cavity and atleast partially surrounding the aeration rotor positioned in the rotorcavity, wherein the shield defines at least one tine port sized andpositioned to allow for ingress and egress of the aeration tines duringrotation of the rotor, and wherein the shield defines a plurality ofsifting ports sized small enough to contain soil plugs within the rotorcavity and large enough to allow soil particles from broken soil plugsto pass through the sifting ports out of the rotor cavity.
 2. The soilaeration apparatus of claim 1, wherein the aeration rotor comprises:first and second carriers rotatable about a first axis; a firsttine-holder shaft extending between the first and second carriers, thefirst tine-holder shaft supporting a first set of aeration tines,wherein the first tine-holder shaft is rotatable with respect to thefirst carrier about a second axis; and a second tine-holder shaftextending between the first and second carriers, the second tine-holdershaft supporting a second set of aeration tines, wherein the secondtine-holder shaft is rotatable with respect to the first carrier about athird axis.
 3. The soil aeration apparatus of claim 2, wherein rotationof the first and second tine-holder shafts turns the first and secondsets of aeration tines to sweep through the first axis.
 4. The soilaeration apparatus of claim 2, wherein the aeration rotor rotates in afirst direction and the first and second tine-holder shafts rotate in asecond direction during rotation of the aeration rotor in the firstdirection.
 5. The soil aeration apparatus of claim 2, wherein theaeration rotor has a radius extending from the first axis to each of thesecond and third axes of about 3.5 inches.
 6. The soil aerationapparatus of claim 2, wherein the aeration rotor has a radius extendingfrom the first axis to each of the second and third axes of betweenabout 3 inches to about 4 inches.
 7. The soil aeration apparatus ofclaim 2, wherein the aeration rotor has a radius extending from thefirst axis to each of the second and third axes of between about 2inches to about 6 inches.
 8. The soil aeration apparatus of claim 7,wherein at least some of the plurality of aeration tines have a lengthexceeding the radius.
 9. The soil aeration apparatus of claim 1, whereinthe shield defines a second tine port sized and positioned to allow foringress and egress of the aeration tines during rotation of the rotor,wherein the aeration tines extend out of the shield only at the firstand second tine ports during rotation of the rotor.
 10. The soilaeration apparatus of claim 1, wherein the shield comprises a frontshield positioned forward of the aeration rotor and a rear shieldpositioned behind the aeration rotor, wherein each of the front and rearshields define a plurality of the sifting ports sized small enough tocontain soil plugs within the rotor cavity and large enough to allowsoil particles from broken soil plugs to pass through the sifting portsout of the rotor cavity.
 11. The soil aeration apparatus of claim 1,wherein the aeration rotor comprises a pulverizing bar configured forpulverizing soil plugs into soil particles in the rotor cavity.
 12. Thesoil aeration apparatus of claim 10, wherein the pulverizing bar ispositioned between about 0.05 inch and about 0.2 inch from an innersurface of the shield.
 13. The soil aeration apparatus of claim 1,wherein each of the aeration tines comprises a knife and a tubeconnected to the knife, wherein the aeration rotor and aeration tinesare configured to pull soil plugs from a ground surface and fling thesoil plugs into the rotor cavity to be pulverized into soil particles bythe aeration rotor within the rotor cavity.
 14. The soil aerationapparatus of claim 1, and further comprising: a motor operably connectedto the aeration rotor to drive rotation of the aeration rotor; and arelief spring system connected between the motor and the aeration rotorand configured to allow for some rotation by the motor when rotation ofthe aeration tines is temporarily slowed or stopped.
 15. The soilaeration apparatus of claim 14, wherein spring capacity of the reliefspring system is equal to or greater than weight of the soil aerationapparatus.
 16. The soil aeration apparatus of claim 15, wherein thespring capacity of the relief spring system is between about 150 poundsand about 600 pounds and the soil aeration apparatus weighs betweenabout 100 pounds and about 500 pounds.
 17. The soil aeration apparatusof claim 1, and further comprising: a frame connected to at least twowheels for travelling over a ground surface, the frame supporting therotor and having a handle positioned and configured to facilitate a userto push the soil aeration apparatus.
 18. A soil aeration apparatuscomprising: a frame connected to at least two wheels for travelling overa ground surface, the frame having a handle positioned and configured tofacilitate a user to push the soil aeration apparatus; an aeration rotoroperably supported by the frame, the aeration rotor comprising first andsecond carriers rotatable with respect to the frame about a first axis,a first tine-holder shaft extending between the first and secondcarriers, the first tine-holder shaft supporting a first set of aerationtines, wherein the first tine-holder shaft is rotatable with respect tothe first carrier about a second axis, and a second tine-holder shaftextending between the first and second carriers, the second tine-holdershaft supporting a second set of aeration tines, wherein the secondtine-holder shaft is rotatable with respect to the first carrier about athird axis; and a motor supported by the frame and operably connected tothe aeration rotor to drive rotation of the aeration rotor such that theaeration tines can penetrate and exit the ground when the aeration rotoris rotated.
 19. The soil aeration apparatus of claim 18, whereinrotation of the first and second tine-holder shafts turns the first andsecond sets of aeration tines to sweep through the first axis.
 20. Thesoil aeration apparatus of claim 18, and further comprising: a shielddefining a rotor cavity and at least partially surrounding the aerationrotor positioned in the rotor cavity, wherein the shield defines atleast one tine port sized and positioned to allow for ingress and egressof the aeration tines during rotation of the rotor, and wherein theshield defines a plurality of sifting ports sized small enough tocontain soil plugs within the rotor cavity and large enough to allowsoil particles from broken soil plugs to pass through the sifting portsout of the rotor cavity
 21. The soil aeration apparatus of claim 18, andfurther comprising: a relief spring system connected between the motorand the aeration rotor and configured to allow for some rotation by themotor when rotation of the aeration tines is temporarily slowed orstopped.
 22. The soil aeration apparatus of claim 21, wherein springcapacity of the relief spring system is equal to or greater than weightof the soil aeration apparatus.
 23. A method of operating a soilaeration apparatus, the method comprising: moving a set of aerationtines in a planetary motion such that the aeration tines revolve about afirst axis and rotate about a second axis different than the first axis;removing soil plugs from a ground surface via the aeration tines;breaking the soil plugs into soil particles via components of the soilaeration apparatus; and returning the soil particles to the groundsurface.
 24. The method of claim 23, the method further comprising:flinging the soil plugs from the aeration tines into a rotor cavity,wherein the soil plugs are broken into soil particles in the rotorcavity.
 25. The method of claim 23, the method further comprising:passing the soil particles through sifting ports sized small enough torestrict passage of the soil plugs and large enough to allow passage ofthe soil particles from broken soil plugs.
 26. The method of claim 23,the method further comprising: walking behind the soil aerationapparatus and holding a handle of the soil aeration apparatus whileoperating the soil aeration apparatus to remove and break soil plugs.27. A soil aeration apparatus comprising: an aeration rotor comprisingat least one set of aeration tines configured for movement in aplanetary motion about an axis; a motor operably connected to theaeration rotor to drive rotation of the aeration rotor such that theaeration tines can penetrate and exit a ground surface when the aerationrotor is rotated; and a frame supporting the aeration rotor and themotor and having a handle configured to be held by a user walking behindthe soil aeration apparatus.
 28. A soil aeration apparatus comprising:an aeration rotor comprising at least one set of aeration tinesconfigured for movement in a planetary motion about an axis, wherein theaeration rotor is configured to remove soil plugs from a ground surfaceand break the soil plugs into soil particles when the aeration rotor isrotated.